1. Field of the Invention
The present invention relates to a liquid jet recording head that discharges recording liquid from the discharge openings as flying droplets to cause them to adhere to a recording medium for printing. The invention also relates to a method for manufacturing such liquid jet recording heads.
2. Related Background Art
The conventional liquid jet recording head is structured in such a manner that as shown in FIGS. 8A and 8B, a first substrate 100, having discharge energy generating devices formed on the silicon substrate, is joined to a second substrate 101, having the recessed portions that form ink flow paths 102; a discharge opening plate 104 provided with discharge openings 103 conductively connected with the ink flow paths 102 to discharge ink; and a recessed portion that constitutes a common liquid chamber 105 that temporarily retains ink to be supplied to each of the ink flow paths 102, and that the joint between the first substrate 100 and the second substrate 101 is sealed by the application of a sealing compound (see Japanese Patent Application Laid-Open No. 55-132253).
Further, a liquid jet recording head for use of color recording is structured in such a manner that as shown in FIG. 10, a first substrate having discharge energy generating devices formed on it is joined to a ceiling plate (a second substrate) 111 having ink discharge nozzles, which is provided with a plurality of liquid chambers 115 each partitioned to receive the supply of ink of different colors, respectively, and that grooves 119 are formed on the second substrate 111 to separate each of the liquid chambers for its reliable partition and division. The partition grooves 118 are filled with a sealing compound.
However, the conventional liquid jet recording head such as shown in FIGS. 8A and 8B tends to allow the sealing compound to flow from the slight gap between the first substrate 100 and the second substrate 101 into the ink flow paths 102, as well as into the discharge opening unit 103, when the joint between the first substrate 100 and the second substrate 101 is sealed by the application of the sealing compound. The recording heads having the ink flow paths 102 or discharge opening unit 103, which are affected by the flow-in of the sealing compound, may cause defective discharges of ink. Therefore, the recording heads showing such defect are regarded as defective products. As a countermeasure to prevent the sealing compound from flowing into the ink flow paths and/or discharging openings, there is a structure disclosed in the specification of Japanese Patent Application Laid-Open No. 2-187351 whereby to provide sealing receptacles 108 on both s the ink flow paths as shown in FIG. 9 for receiving sealing compound. Nevertheless, even with the provision of such receptacles necessary to rigidly control the viscosity of the sealing compound, its tack-free characteristics, the amount of its application, and the like for use.
Further, the grooves 118 for filling the sealing compound used for partitioning each of the liquid chambers, which are arranged between each of the common liquid chambers formed on the second substrate of the conventional color liquid jet recording head (herein-after referred to simply as common liquid chamber partition grooves), are arranged continuously up to the nozzle unit for discharging ink from each of the liquid chambers. When the sealing compound is filled in the common liquid chamber partition grooves 118 for separating colors, there is a need for enabling the flow of the sealing compound to be suspended in the common liquid chamber partition grooves or dummy nozzles so that the sealing compound is not allowed to flow into the nozzles used for discharging ink. However, since the sealing compound flows in the common liquid chamber partition grooves 118 and the dummy nozzles by means of capillary phenomenon, it is extremely difficult to control the filling amount thereof in good precision. In other words, if the filling amount of the sealing compound is too large, it overflows from the dummy nozzles to seal even the ink flow paths eventually. When the filling amount of the sealing compound is too small, the flow thereof is caused to be suspended in the mid way of the common liquid chamber separation grooves. As a result, it becomes impossible to separate the liquid chambers completely, leading to the occurrence of mixed colors. In either case, the production yield is lowered in the sealing step of the manufacture of heads inevitably.
As a countermeasure thereof, there is disclosed a devise regarding the configuration of the common liquid chamber separation walls in the specification of Japanese Patent Application Laid-Open No. 8-11306 (the application No. 6-146244). However, with the adoption of such means as disclosed in this application, it is still difficult to execute the sealing reliably.